uicollectionview inside uitableviewcell scroll will crash due to Index out of range - ios

Question

I learned the UICollectionView inside UITableViewCell from this tutorial.
It works perfectly only when all of the collection views have the same numberOfItemsInSection, so it can scroll and won't cause Index out of range error, but if the collection view cells numberOfItemsInSection are different, when I scroll the collection view it crashes due to Index out of range.
I found the reason that when I scroll the tableview, the collection view cell index path updated according to the bottom one, but the collection view I scrolled is top one so it does't remember the numberOfItemsInSection, so it will crash due to Index out of range.
ps: it is scrollable, but only when that table cell at the bottom, because its numberOfItemsInSection is correspond to that cell and won't cause Index out of range.
This is the numberOfItemsInSection of My CollectionView, i actually have two collection view but i think this is not the problem
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
var numberOfItemsInSection: Int = 0
if collectionView == self.collectionview_categorymenu {
let categories = self.json_menucategory["menu_categories"].arrayValue
numberOfItemsInSection = categories.count
} else {
let menuitems = self.json_menucategory["menu_items"].arrayValue
let item_data = menuitems[self.itemimages_index].dictionaryValue
let menu_item_images = item_data["menu_item_images"]?.arrayValue
numberOfItemsInSection = (menu_item_images?.count)!
print(numberOfItemsInSection)
}
return numberOfItemsInSection
}
This is the cellForItemAt indexPath of my CollectionView:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if collectionView == self.collectionview_categorymenu {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CategoryMenuCell", for: indexPath) as! CategoryMenuCell
return cell
} else {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ItemImagesCell", for: indexPath) as! ItemImagesCell
let menuitems = self.json_menucategory["menu_items"].arrayValue
let item_data = menuitems[self.itemimages_index].dictionaryValue
let menu_item_images = item_data["menu_item_images"]?.arrayValue
print(menu_item_images!)
let itemimage_data = menu_item_images?[indexPath.item].dictionaryValue
print("===\(indexPath.item)===")
let itemimage_path = itemimage_data?["image"]?.stringValue
let itemimage_detail = itemimage_data?["detail"]?.stringValue
if let itemimage = cell.imageview_itemimage {
let image_url = itemimage_path?.decodeUrl()
URLSession.shared.dataTask(with: NSURL(string: image_url!) as! URL, completionHandler: { (data, response, error) -> Void in
if error != nil {
print("error")
return
}
DispatchQueue.main.async(execute: { () -> Void
in
itemimage.image = UIImage(data: data!)!
})
}).resume()
}
if let description = cell.textview_description {
description.text = itemimage_detail
}
if let view = cell.view_description {
view.isHidden = true
}
return cell
}
}

Answer 1

The problem is probaby that you are returning the same number every time for numberOfItemsInSection what you want to do is return the number of items in each array. From the link you sent they do this:
func collectionView(collectionView: UICollectionView,
numberOfItemsInSection section: Int) -> Int {
return model[collectionView.tag].count
}
The other possibility is that you are returning the wrong array when cellForItemAtIndexPath please check that you are using the tag attribute correctly
So they get the count of each array within the model. Without seeing any of your code its very difficult to actually see where your error is coming from.